Dynamo A couple of people wanted me to post about the dynamo so here it is. Around 2000 I started messing around with making a steam powered dynamo for the 2-8-2 to power the lights. The dynamo that came out of this isn’t perfect but can generate 6.2 volts at 1.1 amps. Originally it was used to power the headlight, pressure gauge and water gauge lights. When we changed over to the 12 volt grain of wheat bulbs, the 6.2 volts from the dynamo wasn’t enough so the grain of wheat light bulbs (gauges and classification lights) are powered by a 9 volt battery. The steam end is made from a piece of 1-1/2” diameter brass and the generator end is made out of a piece of steel turned to 1-1/2”. The shaft from the fan is connected to the shaft for the generator by a piece of ½” hex brass (what we had readily available) and is secured to the shafts by a 5-40 socket head cap screw. The socket head cap screw in the generator end keeps the generator/motor from turning. The base is a ½” x 1-1/2” piece of steel. Small flats were milled on the round stock and they are bolted on to the base from the bottom. The steam end was bored out to around 1-3/16” and the fan is made from a ½” hex and 1/32” brass stock. I cut grooves in the flats on the hex for the brass blades, cut the blades from the flat stock and soft soldered the blades to the hex. The fan (which is around 1-1/16” in diameter) is secured to the 1/8” axle by a 5-40 set screw. On either end of the fan I put washers to keep the fan from rubbing into the cap or body. To hold the cap on the end, I drilled and soldered two studs (around a 3-48 size) to the end of the body. The exhaust outlet was silver soldered to the body and was drilled and tapped for a ¼-40 MTP. The steam inlet is a 3/16” copper tube angling up at the 5 o’clock position. Note: I did not balance the fan which causes the lights to flicker. If I were to redo it, I would cut the blades too long and then turn the blades in the lathe to get them to the right diameter and help balance the fan. The steam end cap is made out of brass and has 2 holes drilled for the studs (the nuts are to the right of the cap) and a hole drilled in the center for the axle. If I were to redo this, I would see about installing a bronze bushing in the cap for the axle and would also use something to seal the cap on the body. I used a 12 volt DC motor (bought from Radio Shack) for the generator. I bored out the piece of steel for a slip fit on the motor and bored the opposite end to allow the collar of the motor to stick out of the main bore. I milled a slot in the bottom for the wires and drilled and tapped two 5-40 holes to secure the cap to it. The cap is made from 1-1/2” diameter steel and before the cap is installed, I put a piece of electrical tape over the leads so they can’t short out on the end cap. The generator works decently. Since I did not fine tune it and get the fan balanced, the headlight does flicker. I do use it on occasion, but since it does make some noise, it does take away some from the stalk talk.
Posted on: Thu, 01 Jan 2015 22:04:08 +0000
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